Troubleshoot systemd errors

When running InfluxDB using systemd (Ubuntu, Debian, CentOS), you might encounter errors in the InfluxDB logs (via journalctl -u influxdb) like:

• error msg="Unable to open series file"
• run: open server: open tsdb store: mkdir /var/lib/influxdb/data/_internal/_series/00: permission denied

When InfluxDB is installed with systemd, an influxdb user and group is automatically created. If the user runs an influxd process directly from their login shell, it can generate new series files not accessible by the influxdb user. In this case, when systemd starts the InfluxDB service (via sudo systemctl start influxdb), the InfluxDB process will exit because it cannot access the leftover files owned by the root user.

To resolve this issue, set all files in the InfluxDB directories to be owned by the influxdb user and group. Run the following command:

sudo chown -R influxdb:influxdb /var/lib/influxdb/*

Alternatively, if the data is not important, reset the database by removing all files:

sudo rm -rf /var/lib/influxdb/